At a complete dead end here. Got a Centos background, new to Ubuntu. I've followed various tutorials to get a tigervnc server running, and set up the firewall as follows:
$ sudo ufw allow 5901 # etcnmap localhost tells me that vnc-1 is running, listening on 5901. However, if I do a scan from another box:
# nmap -sT -p 5901 ip4.new.ubuntu.boxIt tells me that 5901 is actually closed. nmap correctly identifies that 22 is open.
I've saved the iptables rules, and they look fine - ports 22 and 5900-5903 are all ACCEPT, and are treated identically. However, I'm not sure that I set this up from ufw - I think I only allow'ed port 5901, as shown above, and the tigervnc installation might have set the other rules.
However, iptables isn't even running. systemctl iptables status can't find the service, but systemctl ufw status reports that ufw is running.
I've tried turing off ufw with ufw disable. From what I've read, this opens all ports, but it doesn't. A Centos box on the network is still reporting that port 22 is open, but all other ports are closed.
So, what on earth is going on? How is port 22 open even with ufw disable? Why isn't iptables running? How exactly does the out-of-the-box firewall work on 19.04? Thanks.
